Field of the Invention
The present invention relates to a solid-state image sensor and a camera.
Description of the Related Art
There is known a technique of implementing focus detection without using any dedicated automatic focus detection (AF) sensor by making a solid-state image sensor used in a digital video camera, digital still camera, or the like have a phase-difference detection function. For example, the solid-state image sensor disclosed in Japanese Patent Laid-Open No. 2011-60815 has openings formed in the light shielding layers of some pixels so as to have eccentric centers relative to the optical axes of microlenses, thereby dividing the pupil of an image sensing lens.
A solid-state image sensor is provided with a well contact region for fixing the potential of a well in which circuit elements such as a photoelectric converter and a transistor are formed. A reference potential line is electrically connected to the well contact region via a contact plug. Japanese Patent Laid-Open No. 2011-60815 has no description or suggestion about how to arrange well contact regions.